Method and apparatus for the extrusion of lead and other metals



Nov. 20, 1934. HILL 7 1,981,045

METHOD AND APPARATUS FOR THE EXTRUSION OF LEAD AND OTHER METALS Filed Sept. 24, 1952 WW M ATTORNL'Y} Patented Nov. 20, 1934 METHOD AND APPARATUS FOR THE EX- TRUSION OF LEAD AND OTHER METALS Harry Hill, Kent, England, assignor to Callenders Cable and Construction Company Limited,

London, England, a British Company Application September 24, 1932, Serial No. 634,634 In Great Britain November 9, 1931 Claims. (Cl. 207-) This invention relates to the extrusion of lead and other metals from a container into which the liquid metal is poured and from which it is exfound in the uncertainty of producing perfect joining up of the incoming charge of molten metal 10 with the remnant of the previous charge which is in a solidified condition at the bottom of the container. If effective joining is not obtained the resulting extruded body does not have a homogeneous structure. This is due to the fact that the face of the remnant of the solidified old charge, on to which the molten metal of the new charge is poured, is covered with a film of oxide and other substances which may remain localized in the charge. This is due to the failure of the incoming molten metal to melt away sufficiently the face of the old charge and thereby remove the film of oxide and other material.

In accordance with the present invention we adopt a method of pouring of the molten metal which removes the difi'iculty above referred to. In this method the whole or the greater part of the incoming charge of molten metal is caused to impinge or flow over the face of the old charge and thereby melt away the old charge to a substantial depth, liberating the film of oxide and other material and carrying it away as the charge flows towards other parts of the container. This method has the effect of preventing the localization of the material of the film in the charge and is preferably carried out so as to cause the material of the film to travel to the surface of the charge at the open end of the container so that it may be removed after pouring has been completed.

The apparatus for carrying out this method of pouring consists of a portable tube which can be placed inside the container with its lower end resting upon or in proximity to the surface of the old charge; The tube has a handle or other means by which it can be supported in the required position inside the container and to enable it to be removed from the container at the termination of the pouring process. The lower end of the tube has one or more openings for the discharge of the molten metal from the tube on to the surface of the old charge. The upper end of the tube conveniently is enlarged to facilitate the pouring of the molten metal into the tube from the pot container or monometer.

One form of construction of apparatus for carrying out the invention is illustrated by way of example in the accompanying drawing wherein:--

Figure 1 shows in section a container of a lead press,

Figure 2 is an elevation drawn to a larger scale of the lower end of the pouring tube,

Figure 3 is an inverted plan view of Figure 2, and

Figure 4 is a view in elevation of a detail of a sieve or screen for insertion in the pouring tube.

In Figure 1 the remaining part of an old charge of lead is indicated at 1. This is disposed at the lower end of a container 2. When the latter is filled with lead it is raised by a hydraulic ram so that the fixed ram 3 enters the top of the container to extrude the lead through a die in the usual manner.

The remnant 1 of the old charge is in a solid state and to provide for an effective joining up of this remnant with the new charge of molten metal, the latter is poured into the container 2 through a tube 4 which conveniently is curved at its upper portion, the latter terminating in an enlarged part 5. The tube 4 is held in the container 2 by means of a handle 6, the upper end 5 of the tube being placed beneath the spout 7 of a tube 8, the latter receiving the molten metal from the lead pot (not shown). The tube 8 is preferably in the form of a closed tube as illustrated and is supported upon the top of the container 2 by a bracket 9. To prevent the passage of any non-molten material from reaching the container 2 the upper parts of the tube 4 are provided with a removable sieve or screen 10 having a lip 11 to enable it to be hung over the edge of the mouth of the tube. The screen'hangs vertically in the mouth of the tube and extends across the passage from the mouth intothe tube in the manner shown in Figure 1.

The lower end of the tube 4 is provided with a number of openings 12 as shown in Figure 2. These openings provide for the radial discharge of the molten metal over the surface of the remainder of the old charge.

To fill up the container with molten metal the tube 4 is placed in the container 2 with its lower end resting on the surface of the charge 1, the tube 4 being held in position by the handle 6 with the upper end of the tube underneath the spout 7. The new charge of molten metal is then poured down thetube 4 until the operator feels in a few seconds, that a crater has been formed in the upper part of the old charge. The pouring process being continued the tube 4 will then be raised a short distance and moved to another position in the container in order to produce the formation of another crater. This method of operation is continued until the container is practically filled with metal. When this occurs,

the tube 4 is withdrawn and the whole charge bracket 9 being first swimg or otherwise moved out of the way.

In the pouring'process the molten metal impinges uponor flows over the surface of the remaining part of the old charge, melting the latter in the neighbourhood of the end of the tube. By moving the end of the tube about in the container as the remeltingof the old charge is continued, the old charge can be melted to a depth of an inch or more; With such an arrangement the flow of the molten metal carries with it the part of the old charge which has been remelted and tends to bring it and the oxide film towards the open upper end of the container 2. When the pouring has been completed and the tube 4 removed from the container, the surface of the charge can then be skimmed for the removal of oxide and other foreign material.

The invention is not limited to the precise details of construction of the apparatus employed for the pouring method, for example, the openings in the lower end of the pouring tube need not necessarily be formed in the actual end of the tube. They might, for example be openings provided close to this edge, or additional openings spaced away from the edge might be provided between those illustrated in Figure 2 of the. drawing. Other arrangements, however, might be adopted. The screen 10 may consist of a perforated metal sheet or maybe made of wire gauze. The lip 11 permits the screen .to be removed readily from the tube 4 for cleaning purposes.

What I claim as my invention and desire to secure by Letters Patent is:

. 1. In the extrusion of lead and other metals from a, container, the method of melting the surface of the"old charge to produce a homogeneous joint between the 01d and new charges which consists in causing a stream of molten metal forming part of the new charge to impi'nge upon a part of the surface of the old charge from a point on this surface to form a cavity of molten metal at this part, and then discharging the molten metal into this cavity from a point beneath the surface thereof and causing the metal to flow laterally in a number of streams over the surface of the old charge, these steps being repeated for other parts of the surface of the old charge so as to melt the latter to a substantial depth and produce thorough intermelting of the old and new charges and liberate the impurities in the old charge therefrom, and prbduce a homogeneous joint between the old and new charges.

2. The method of introducing molten metal into a container onto the top surface of a solidified charge therein, which comprises simultaneously discharging the metal downwardly and laterally over a plurality of successive small areas of the surface-of the solidified charge.

3. The method of introducing molten metal into a container onto the top surface of a solidified charge therein, which comprises simultaneously discharging the metal downwardly and laterally over a plurality of successive small areas of the surface of the solidified charge and increasing the depth of penetration of the downwardly flowing metal in each of the successive small areas of the surface of the solidified charge.

4. A filling tube of the class described, comprising a tube having an open lower end and means adjacent the end providing a plurality of laterally opening discharge ports, and manipulating means adjacent the upper end of said member, said manipulating means enabling the member to be raised and lowered during the pouring operation and enabling it to be moved laterally.

5. A device for use in the extrusion of lead and other metals from a container consisting of of the tube.

HARRY HILL. 

